John A. Ruben is a researcher in
Zoology
Zoology ( , ) is the scientific study of animals. Its studies include the anatomy, structure, embryology, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and ...
and
Vertebrate
Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain.
The vertebrates make up the subphylum Vertebra ...
paleontology
Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure ge ...
at the
Oregon State University
Oregon State University (OSU) is a Public university, public Land-grant university, land-grant research university in Corvallis, Oregon, United States. OSU offers more than 200 undergraduate degree programs and a variety of graduate and doctor ...
in
Corvallis, United States. Much of his published research is focused on studying the
respiratory system
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies grea ...
in birds, in order to contradict the theory of
theropod
Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...
an ancestry of birds, as well as their
metabolism
Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...
.
Research
Ruben has questioned for many years the theory that birds descend from small
carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose nutrition and energy requirements are met by consumption of animal tissues (mainly mu ...
dinosaurs of suborder
. He suggest theropods had a
diaphragma driven respiratory system which could not have evolved into the complex
air sacs in birds (but the presence of air sacs in
saurischia
Saurischia ( , meaning "reptile-hipped" from the Greek ' () meaning 'lizard' and ' () meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia), classified by their hip structure. Saurischia and Ornithi ...
n dinosaurs has been demonstrated by highly pneumatic fossil bones of e.g. ''
Aerosteon'' and ''
Tataouinea''). While some have claimed Ruben's research to be flawed, his papers have, nevertheless, appeared in highly regarded, heavily peer-reviewed journals such as Science, Nature and the Journal of Morphology. He has done some research on the dinosaurs ''
Scipionyx'' and ''
Sinosauropteryx'', from which he gives his arguments. Ruben also took part in the 2009 discovery of a close correlation between the immobilized
thighbone and complex
respiratory systems in birds.
Research on the
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
animal ''
Microraptor
''Microraptor'' (Greek language, Greek, μικρός, ''mīkros'': "small"; Latin language, Latin, ''raptor'': "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovere ...
'' has also led Ruben to suggest that
Dromaeosauridae
Dromaeosauridae () is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from ...
, for a long time regarded as
feathered dinosaurs
A feathered dinosaur is any species of dinosaur possessing feathers. That includes all species of birds, and in recent decades evidence has accumulated that many non-avian dinosaur species also possessed feathers in some shape or form. The exte ...
, actually represent
flightless descendants of older birds, as he said: "We think the evidence is showing that these animals which are usually considered dinosaurs were actually descended from birds, not the other way around". Ruben sees it more possible that perhaps a creature like the
diapsid
Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeosc ...
reptile
Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...
''
Longisquama'' represents the ancestor to birds.
John Ruben about ''Longisquama''.
References.
External links
{{DEFAULTSORT:Ruben, John
21st-century American zoologists
American paleontologists
Oregon State University faculty
Living people
Year of birth missing (living people)